Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
You are mostly likely blocking traffic from outside India, or TCP port 80 just isn't open (for http). If you need to block for either reason then you will need to use DNS validation instead of HTTP validation for your domain.
http-01 validation does not work if you block connections from the rest of the world. You have three options:
allow connections from the rest of the world, always
allow connections from the rest of the world, only during validation (certbot has --pre-hook and --post-hook that you can use to issue commands to your firewall, I don't know your client)
use the dns-01 challenge instead of http-01 as @webprofusion said. be aware that if the same firewall is protecting your authoritative nameserver, dns-01 will fail as well.
It looks like your authoritative nameservers (one of them, at least) responds to me.
$ dig @dns5.tatacommunicationsdns.com. a dm.mcgm.gov.in
; <<>> DiG 9.18.0-2ubuntu2-Ubuntu <<>> @dns5.tatacommunicationsdns.com. a dm.mcgm.gov.in
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25887
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 6
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;dm.mcgm.gov.in. IN A
;; ANSWER SECTION:
dm.mcgm.gov.in. 14400 IN A 59.163.51.179
;; AUTHORITY SECTION:
mcgm.gov.in. 86400 IN NS dns2.tatacommunicationsdns.com.
mcgm.gov.in. 86400 IN NS dns5.tatacommunicationsdns.com.
mcgm.gov.in. 86400 IN NS dns3.tatacommunicationsdns.com.
mcgm.gov.in. 86400 IN NS dns1.tatacommunicationsdns.com.
mcgm.gov.in. 86400 IN NS dns4.tatacommunicationsdns.com.
;; ADDITIONAL SECTION:
dns1.tatacommunicationsdns.com. 14400 IN A 115.112.250.115
dns2.tatacommunicationsdns.com. 14400 IN A 195.219.235.85
dns3.tatacommunicationsdns.com. 14400 IN A 209.58.67.115
dns4.tatacommunicationsdns.com. 14400 IN A 66.198.171.70
dns5.tatacommunicationsdns.com. 14400 IN A 121.241.244.165
;; Query time: 250 msec
;; SERVER: 121.241.244.165#53(dns5.tatacommunicationsdns.com.) (UDP)
;; WHEN: Fri Feb 25 11:27:36 CET 2022
;; MSG SIZE rcvd: 259